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The present study investigates U.S. Department of Agriculture inspection records in the Agricultural Quarantine Activity System database to estimate the probability of quarantine pests on propagative plant materials imported from various countries of origin and to develop a methodology ranking the risk of country–commodity combinations based on quarantine pest interceptions. Data collected from October 2014 to January 2016 were used for developing predictive models and validation study. A generalized linear model with Bayesian inference and a generalized linear mixed effects model were used to compare the interception rates of quarantine pests on different country–commodity combinations. Prediction ability of generalized linear mixed effects models was greater than that of generalized linear models. The estimated pest interception probability and confidence interval for each country–commodity combination was categorized into one of four compliance levels: "High," "Medium," "Low," and "Poor/Unacceptable," Using K‐means clustering analysis. This study presents risk‐based categorization for each country–commodity combination based on the probability of quarantine pest interceptions and the uncertainty in that assessment. [ABSTRACT FROM AUTHOR]

This study compares four models for predicting the potential distribution of non-indigenous weed species in the conterminous U.S. The comparison focused on evaluating modeling tools and protocols as currently used for weed risk assessment or for predicting the potential distribution of invasive weeds. We used six weed species (three highly invasive and three less invasive non-indigenous species) that have been established in the U.S. for more than 75 years. The experiment involved providing non-U. S. location data to users familiar with one of the four evaluated techniques, who then developed predictive models that were applied to the United States without knowing the identity of the species or its U.S. distribution. We compared a simple GIS climate matching technique known as Proto3, a simple climate matching tool CLIMEX Match Climates, the correlative model MaxEnt, and a process model known as the Thornley Transport Resistance (TTR) model. Two experienced users ran each modeling tool except TTR, which had one user. Models were trained with global species distribution data excluding any U.S. data, and then were evaluated using the current known U.S. distribution. The influence of weed species identity and modeling tool on prevalence and sensitivity effects was compared using a generalized linear mixed model. Each modeling tool itself had a low statistical significance, while weed species alone accounted for 69.1 and 48.5% of the variance for prevalence and sensitivity, respectively. These results suggest that simple modeling tools might perform as well as complex ones in the case of predicting potential distribution for a weed not yet present in the United States. Considerations of model accuracy should also be balanced with those of reproducibility and ease of use. More important than the choice of modeling tool is the construction of robust protocols and testing both new and experienced users under blind test conditions that approximate operational conditions. [ABSTRACT FROM AUTHOR]

Biomechanical properties can be important parameters in resistance of plants to herbivorous insects. As plants age, however, there can be dramatic changes in physical defenses that can then influence their susceptibility to insect herbivores. We measured changes in leaf biomechanical properties during ontogeny of Poa species and the relationship of these changes to the development of a generalist herbivore, the black cutworm, Agrotis ipsilon Hufnagel ( Lepidoptera: Noctuidae), was investigated. Larvae were reared on two representative age classes, i.e., young (<60 days after planting) and old (>1 year after planting), of foliage in laboratory assays. Foliage generally reaches a peak fracture force between 80 and 109 days after planting depending on grass type. Foliage from old plants was significantly tougher than that of young plants, and black cutworm larvae reared on foliage from young plants gained significantly (ca. four times) more weight than those fed on foliage from old Poa plants. In addition, fracture force has a negative relationship with black cutworm development. Plant fiber, particularly neutral detergent fiber accounted for 65 and 46% of the variation in fracture force and larval development, respectively. These results provide additional insight into how plant ontogeny influences physical defenses to an insect herbivore in a grass system. Likewise, this is seemingly the first study to suggest a mechanism for host plant resistance to black cutworm. Plant fiber may be a useful trait to explore in plant improvement programs in which black cutworm is a primary pest (e.g., managed turfgrass). [ABSTRACT FROM AUTHOR]